Increasingly, telephone calls are being established as voice over IP (VOIP) calls where audio or video signals are digitized, packetized, and sent across a packet switched network, rather than being sent as a raw analog signal across a circuit. As such, end user devices transmit call data to a far end IP address, where the audio or video will be rendered. To facilitate the initial connection between devices, telephony application servers (TAS) are deployed within the network. To establish a new call, an end user device communicates with a TAS according to the session initiation protocol (SIP). The TAS then negotiates the connection and informs the user devices at the far end IP address to which data should be transmitted for the call.